/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.header;

import javax.servlet.http.HttpServletRequest;

import org.apache.http.HeaderElement;
import org.apache.http.ParseException;
import org.apache.jackrabbit.webdav.DavConstants;

/**
 * <code>DepthHeader</code>...
 */
public class DepthHeader implements org.apache.http.Header, DavConstants {

	// private static Logger log = LoggerFactory.getLogger(DepthHeader.class);

	/**
	 * Convert the String depth value to an integer.
	 * 
	 * @param depth
	 * @return integer representation of the given depth String
	 * @throws IllegalArgumentException
	 *             if the String does not represent a valid depth.
	 */
	private static int depthToInt(String depth) {
		int d;
		if (depth.equalsIgnoreCase(DavConstants.DEPTH_INFINITY_S)) {
			d = DavConstants.DEPTH_INFINITY;
		} else if (depth.equals(DavConstants.DEPTH_0 + "")) {
			d = DavConstants.DEPTH_0;
		} else if (depth.equals(DavConstants.DEPTH_1 + "")) {
			d = DavConstants.DEPTH_1;
		} else {
			throw new IllegalArgumentException("Invalid depth value: " + depth);
		}
		return d;
	}

	/**
	 * Retrieve the Depth header from the given request object and parse the
	 * value. If no header is present or the value is empty String, the
	 * defaultValue is used ot build a new <code>DepthHeader</code> instance.
	 * 
	 * @param request
	 * @param defaultValue
	 * @return a new <code>DepthHeader</code> instance
	 */
	public static DepthHeader parse(HttpServletRequest request, int defaultValue) {
		String headerValue = request.getHeader(HEADER_DEPTH);
		if (headerValue == null || "".equals(headerValue)) {
			return new DepthHeader(defaultValue);
		} else {
			return new DepthHeader(depthToInt(headerValue));
		}
	}

	private final int depth;

	/**
	 * Create a new <code>DepthHeader</code> with either value {@link #DEPTH_0
	 * 0} or {@link #DEPTH_INFINITY infinity}.
	 * 
	 * @param isDeep
	 */
	public DepthHeader(boolean isDeep) {
		this.depth = (isDeep) ? DEPTH_INFINITY : DEPTH_0;
	}

	/**
	 * Create a new <code>DepthHeader</code> from the given integer.
	 * 
	 * @param depth
	 */
	public DepthHeader(int depth) {
		if (depth == DEPTH_0 || depth == DEPTH_1 || depth == DEPTH_INFINITY) {
			this.depth = depth;
		} else {
			throw new IllegalArgumentException("Invalid depth: " + depth);
		}
	}

	/**
	 * @return integer representation of the depth indicated by the given
	 *         header.
	 */
	public int getDepth() {
		return depth;
	}

	public HeaderElement[] getElements() throws ParseException {
		// TODO Auto-generated method stub
		return null;
	}

	/**
	 * Return {@link DavConstants#HEADER_DEPTH Depth}
	 * 
	 * @return {@link DavConstants#HEADER_DEPTH Depth}
	 * @see DavConstants#HEADER_DEPTH
	 * @see Header#getHeaderName()
	 */
	public String getName() {
		return DavConstants.HEADER_DEPTH;
	}

	/**
	 * Returns the header value.
	 * 
	 * @return header value
	 * @see Header#getHeaderValue()
	 */
	public String getValue() {
		if (depth == DavConstants.DEPTH_0 || depth == DavConstants.DEPTH_1) {
			return String.valueOf(depth);
		} else {
			return DavConstants.DEPTH_INFINITY_S;
		}
	}

}